![]() ![]() The authors identified 14 vortices during a single 55-minute observing run, which lasted for an average of about 13 minutes. These different gases all exhibited vortex behavior, aligned with the same spot on the photosphere. Using data from SDO and SST, they measured the motion of various elements in the Sun's atmosphere (iron, calcium, and helium) via the Doppler effect. To crack the problem of the super-hot corona, the researchers focused their attention on the chromosphere. ![]() The chromosphere and corona are not seen without special equipment (except during total solar eclipses), but they can be studied with dedicated solar observatories. The chromosphere is far less dense but hotter the corona ("crown") is still hotter and less dense, making an amorphous cloud around the sphere of the Sun. The photosphere is the visible bit of the Sun, what we typically think of as the "surface." It exhibits the behavior of rising gas and photons from the solar interior, as well as magnetic phenomena such as sunspots. The Sun's atmosphere is divided into three major regions: the photosphere, the chromosphere, and the corona. Such acceleration could bring about the incredibly high temperatures observed in the Sun's outer atmosphere. Comparing these observations to computer simulations, the authors determined the vortices could be produced by a magnetic vortex exerting pressure on the gas in the atmosphere, accelerating it along a spiral trajectory up into the corona. They measured the shape of the swirls as a function of height in the atmosphere, determining they grow wider at higher elevations, with the whole structure aligned above a concentration of the magnetic field on the Sun's surface. Sven Wedemeyer-Böhm and colleagues identified the vortices using NASA's Solar Dynamics Observatory (SDO) spacecraft and the Swedish Solar Telescope (SST). There are about 10 thousand swirls in evidence at any given time. The recent discovery of atmospheric "tornadoes"-swirls of gas over a thousand kilometers in diameter above the Sun's surface-may provide a possible answer.Īs described in Nature, these vortices occur in the chromosphere (the layer of the Sun's atmosphere below the corona) and they are common. However, the diffuse solar atmosphere is magnetically too quiet on the large scales. Most solar physicists suspect the process is magnetic, since the strong magnetic fields at the Sun's surface drive much of the solar weather (including sunspots, coronal loops, prominences, and mass ejections). The surrounding corona rises to over a million K, but the heating process has not been identified. The Sun's surface, which emits almost all the visible light, is about 5800 Kelvins. The corona does not have an upper limit.One of the abiding mysteries surrounding our Sun is understanding how the corona gets so hot. The corona cannot be seen with the naked eye except during a total solar eclipse, or with the use of a coronagraph. The temperature in the corona is 500,000 K (900,000 degrees F, 500,000 degrees C) or more, up to a few million K. Transition Region - The transition region is a very narrow (60 miles / 100 km) layer between the chromosphere and the corona where the temperature rises abruptly from about 8000 to about 500,000 K (14,000 to 900,000 degrees F, 7700 to 500,000 degrees C).Ĭorona - The corona is the outermost layer of the Sun, starting at about 1300 miles (2100 km) above the solar surface (the photosphere). The temperature in the chromosphere varies between about 4000 K at the bottom (the so-called temperature minimum) and 8000 K at the top (6700 and 14,000 degrees F, 37 degrees C), so in this layer (and higher layers) it actually gets hotter if you go further away from the Sun, unlike in the lower layers, where it gets hotter if you go closer to the center of the Sun. Most of the photosphere is covered by granulation.Ĭhromosphere - The chromosphere is a layer in the Sun between about 250 miles (400 km) and 1300 miles (2100 km) above the solar surface (the photosphere). The temperature in the photosphere varies between about 6500 K at the bottom and 4000 K at the top (11,0 degrees F, 62 degrees C). It reaches from the surface visible at the center of the solar disk to about 250 miles (400 km) above that. Photosphere - The photosphere is the deepest layer of the Sun that we can observe directly. IRIS will focus its investigation on the Chromosphere and Transition Region. The outer layers are the Photosphere, the Chromosphere, the Transition Region and the Corona. The inner layers are the Core, Radiative Zone and Convection Zone. This graphic shows a model of the layers of the Sun, with approximate mileage ranges for each layer: for the inner layers, the mileage is from the sun's core for the outer layers, the mileage is from the sun's surface. ![]()
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